1. Field of the Invention
This invention relates generally to automotive accessories and more particularly to devices which raise and lower a spare tire from beneath the bed of a pickup truck.
2. Description of the Prior Art
The spare tire for a pickup truck is typically mounted beneath the pickup truck's bed and near the rear axle. While some imported pickup trucks include a winch type lowering mechanism for raising and lowering the spare tire, most American pickup trucks have their spare tire held in position with a cross strap bolted to their frame.
Because of this arrangement, it is difficult and inconvenient to remove and replace a spare tire from most American pickup trucks. For example, to remove the pickup truck's spare tire, a wing nut which holds one end of the cross strap is loosened with one hand, while the other hand must hold the cross strap to prevent the spare tire from crashing down after the wing nut is removed. To replace the spare tire, the entire weight of the spare tire and the cross strap assembly must be held with one hand while the wing nut is replaced on the mounting bolt with the other hand.
A number of prior art patents have addressed this problem. For example, U.S. Pat. No. 4,329,107 of Smith discloses a spare tire carrier including a lever arm pivotally attached to a pickup truck's rear bumper, a pair of pulleys attached to the pickup truck's frame, and a cable attached to the lever and trained over the pulleys. The free end of the cable is attached to a member which engages the hub of the spare tire's wheel. A similar device is taught in U.S. Pat. No. 3,390,864 of Searcy.
A different approach to lowering a pickup truck's spare tire is described in U.S. Pat. No. 4,060,171 of Ludwig and British Pat. No. 1,120,909 of Simca. Both Ludwig and Simca teach a spare tire carrier including a pivotal support brace, and a plurality of linkage members coupling a free end of the support brace to the pickup truck's frame. Lowering mechanisms are provided to extend the length of the linkages and thus lower the pivotal support brace to allow the removal of the spare tire.
A problem with prior art spare tire lowering mechanisms is that they are relatively complex and are difficult to install. Furthermore, the prior art devices require that the existing spare tire cross strap be removed in order to install the new mechanism. Because of these problems, the tire lowering devices of the prior art have not been widely adopted.